OF LIMAX AGRESTIS, ETC. 573 



some objection might be taken on tbe ground that there is no very 

 strong a priori reason why an Arion should not exist in Greenland, 

 considering that it exists in Iceland, the land shells of which 

 Mcirch himself^ allows are nearly allied to those of Greenland, and 

 is not only an acknowledged member of the circumpolar fauna ^, 

 but the most abundant of all slugs in Finmark and Lapland. It is 

 curious — and not only curious, but in view of the question of the 

 distribution of Fasciola hepatica also important — to note what 

 follows. In 1875 Dr. Morch appears, after thus adding Arion 

 hortensis to his former list of Greenland mollusca, to have been 

 content to leave the entry of ' Limax agrestis, L., according to 

 Wormskiold,' untouched, though in smaller type, feeling probably 

 that as the entry of the animal was overtly made only on the 

 authority of Wormskiold, he was in no way pledged either to 

 holding that it was Limax agrestis, and not Limax ienellus^ which 

 existed in Greenland, or indeed to holding that any Limax what- 

 ever existed there. What completes my case is the fact that in 

 1877, when preparing a list of the Greenland mollusca for the 

 English translation of Dr. Rink's * Gronland,' of 1857, Dr. Morch 

 omits all mention of Limax agrestis altogether, and his entry runs 

 as follows (p. 436) : — 



* Class i. ANDROG YNA. 

 Order i. Geophila, Fer. 



I. Arion fuscus. Probably introduced.' 



If we follow Dr. Morch, therefore, we shall strike Limax agrestis 

 out of the list of Greenland mollusca, and hold that A^ion hortensisy 

 which exceeds it in number in other circumpolar regions, has in 

 Greenland displaced, or at any rate replaced, it altogether. 



If, however, Limax agrestis, notwithstanding the advantage which 



^ See Manual, p. 135. 



' Middendorff, indeed, in his * Sibirische Reise,' ii. 1851, p, 419, omits the name 

 of this small slug from his list of Circumpolar Freshwater and Land Molluscs, but five 

 pages farther on, 1. c, says in a note, * Vielleicht ist Limax (Arion) suh-fuscus, Drap. 

 (Drap. "Moll." p. 125, pi. ix. 8 ; Limax fasciatus, Nillsen, " Hist. Moll, Suec." 1822, 

 p. 3) eine circumpolare Art dieses Geschlechtes ;' and he proceeds to note ita 

 discovery by himself within the polar circle in Finland, feeding on sphagnum, as also 

 in Lapland, feeding on fungi, up to 69° N. Lat. Schrenk ('Reise in Amurlande/ 

 1859-1867, ii. p. 692), whilst identifying the Limax suh-fuscus of Draparnaud with 

 the Arion hortensis of F^russac, and so with the Limax fuscus of Miiller and Linnaeus, 

 confirms the view as to its circumpolar character, and uses it as an argument for ita 

 being indigenous in America. 



